CONN 

S 

43 

.E22 

no.l84 


Digitized  by  the  Internet  Archive 

in  2011  with  funding  from 

LYRASIS  members  and  Sloan  Foundation 


http://www.archive.org/details/spraytreatmentetOObrit 


I'Aa^'.^     )'6-i 


CONNECTICUT 


Agricultural  Experiment  Station 


NEW  HAVEN,  CONN. 


BULLETIN  184,  DECEMBER,  1914. 


SPRAY  treatment,  ETC.,  for  ORCHARDS. 


CONTENTS. 


Page 

Officers  and  Staff 2 

Spray    Treatment,    etc.,    for 

Orchards     3 

Winter  Treatment 3 

Pruning  as  a  Control  Measure  3 

Winter  Spraying 4 

What  to  Use 5 

Lime-Sulphur  Mixtures    .      5 

Miscible  Oils 6 

Lime-Sulphur  versus  Misci- 
ble Oils 6 


Page 

Summer  Spraying 6 

Apple 6 

Pear 8 

Peach 8 

Plum 8 

Cherry 9 

Quince 9 

Directions  for    Making  Spray 

Mixtures 10 

Cautions 11 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Con- 
necticut who  apply  for  them,  and  to  others  so  far  as  the  editions 
permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION. 


OP'KICERS     AND     STAFF". 


BOARD  OF  CONTkOl.. 
His   Excellency,    Simeon    E.    Baldwin,   ex-officin,   President. 

Prof.  H.  W.  Conn,  Vice  President  Middletown 

George  A.  Hopson,  Secretary   Wallintrford 

E.  H.  Jenkins,  Director  and  Treasurer Xew  Haven 

Joseph  W.  Alsop  Avon 

Wilson  H.   Lee    Orange 

Prank   H.    Stadtmueller    Elmwood 

James  H.  Webb  •  • Hamden 


Administration. 


E.  H.  Jenkins,  Ph.D.,  Director  and  Treasurer. 
Miss  V.  E.   Cole  .  Librarian  and  Stenographer. 
Miss  L.  M.  Brautlecht,  Bookkeeper  and  Stenographer. 
William  Veitch, 7n  charge  of  Buildings  and  Grounds. 


Chemistry. 

Analytical  Laboratory.  John  Phillips  Street,  M.  S.,  Chemist  in  Charge. 
E.    Monroe  Bailey,   Ph.D.,   C.   B.   Morison,   B.S., 
C.   E.   Shepard,  G.   L.   Davis,  Assistants. 
Hugo  Lange,   Laboratory   Helper. 
V.    L.    Churchill,   Sampling  Agent. 
Miss  E.   B.  Whittlesey,  Stenographer. 


Proteid  Research. 


T.   B.    Osborne,   Ph.D.,  Chemist  in   Charge. 
Miss  E.  L.  Ferry,  M.S.,  Assistant. 


IBotany. 


G.    P.    Clinton,    Sc.D.,    Botanist. 
E.  M.  Stoddard,  B.S.,  Assistant  Botanist. 
Miss    E.    B.    Whittlesey,    Herbarium   Assistant. 
G.  E.  Graham,  General  Assistant. 


Entomology. 


W.   E.   Britton,  V 11. T).,  Entomologist ;  State  Entomologist. 
B.   H.   Walden,  B.Agr.,  First  Assistant. 
Q.   S.  Lowry,  B.Sc,  I.  W.  Davis,  B^Sc, 

M.  p.  Zappe,  B.S.   Assistants. 
Miss   F.   M.   Valentine,   Stenographer. 


Forestry. 


Walter    O.    Filley,    Forester;    also    State    Forester 

and   State   Forest   Fire    Warden. 
A.   E.   Moss,  M.   F.,   Assistant  Station  Forester. 
Miss   E.   L.   Avery,   Stenographer. 


Plant   Breeding. 


H.  K.  Hayes,  M.S.,  Plant  Breeder. 
C.  D.   Hubbell,  Assistant. 


Vegetable    Growing. 


Howard  F.   Huber,  B.S. 


SPRAY  TREATMENT,  ETC.,  FOR  ORCHARDS. 

By  W,  E.  Britton,  Entomologist,  and 
G.  P.  Clinton,  Botanist. 

This  bulletin  has  been  prepared  to  meet  a  constant  and  grow- 
ing demand  for  information  regarding  the  general  spraying 
of  orchards  in  Connecticut.  More  specific  and  detailed  ac- 
counts of  the  various  insect  and  fungous  pests  of  orchards 
may  be  found  in  the  Spray  Calendar  and  in  the  reports  of  this 
Station,  especially  those  of  the  Entomologist,  the  Botanist,  and 
in  "Tests  of  Summer  Sprays  on  Apples  and  Peaches",  Reports 
1910,  page  583,  and  1911,  page  347.  Some  of  these  are  out 
of  print  and  can  no  longer  be  supplied. 

If  the  orchardist  finds  troubles  not  readily  recognized  by 
means  of  the  publications  just  mentioned,  or  if  they  are  new 
to  him,  he  should  send  specimens  to  the  Station  for  identifica- 
tion and  for  advice  about  treatment.  All  such  specimens 
should  be  placed  in  a  strong  paper,  wood  or  metal  box,  so  as 
not  to  be  crushed  in  the  mails.  All  communications  are  an- 
swered when  the  sender's  name  and  address  accompany 
specimens. 

WINTER  TREATMENT. 

Pruning  as  a  Control  Measure. 

In  most  peach  and  apple  orchards  it  is  the  usual  practice  to 
prune  before  spraying  the  dormant  trees,  especially  before  the 
March  spraying  with  lime-sulphur  or  with  miscible  oil.  All  sur- 
plus wood  may  then  betaken  out,  thus  leaving  less  bark  surface  to 
be  covered  with  the  liquid.  If  the  trees  are  attacked  by  San 
Jose  Scale  or  any  other  kind  of  scale  insect,  the  worst  infested 
branches  should  be  removed.  All  branches  showing  injury 
from  the  attack  should  be  headed  back  in  order  to  get  a  strong- 
er growth  from  fewer  buds. 

Winter  pruning  is  even  more  essential  for  fungous  troubles 
than  for  insects.  Of  course  one  of  the  chief  reasons  for 
pruning  is  to  take  out  unnecessary  and  interfering  branches 
and  shape  up  the  tree,  with  resulting  improved  dry  air  drain- 
age whereby   infection   by   fungi   is   lessened,   but   even   more 


4  CONNECTICUT  EXPERIMENT  STATION     BULLETIN    184. 

important  is  the  removal  of  dead  limbs  and  twigs  and  those 
showing  diseased  areas  and  cankers  in  the  bark,  as  all  these 
are  frequently  the  carriers  of  the  winter  stage  of  injurious 
fungi.  When  it  is  not  advisable  to  remove  the  cankered 
branch  or  trunk,  the  infected  area  should  be  carefully  removed 
by  cutting  clear  to  the  healthy  bark  and  scraping  out  all  the 
intermediary  tissues.  These  scraped  areas  and  the  cut  ends 
of  the  larger  branches  should  be  painted  over  when  dry  with 
white  lead  or  coal  tar. 

After  this  pruning  has  been  done  the  tree  should  be  thor- 
oughly coated  with  spray.  It  is  a  good  practice  to  bum  all 
diseased  or  infected  branches  w^hich  have  been  cut  from  the 
trees. 

For  the  blight  on  pear,  also  on  apple  and  quince  when  they 
are  seriously  affected  by  this  bacterial  disease,  winter  pruning 
is  especially  desirable,  since  the  re-inoculation  of  the  germs  in 
the  freshly  cut  surfaces  is  then  much  less  likely  than  during  the 
growing  season.  Even  in  winter,  however,  it  is  best  to  cut  oft 
the  branches  some  distance  below  the  diseased  parts  and  wipe 
the  pruning  tool  frequently  with  a  cloth  moistened  in  carbolic 
acid  or  corrosive  sublimate  solution,  to  kill  any  accidentally 
attached  germs. 

For  cherries  and  plums  attacked  by  black  knot,  pruning  in 
late  fall  or  in  winter  before  the  winter  spore  stage  starts  to 
germinate  is  likewise  desirable.  Cutting  out  the  knots  has  not 
been  found  very  satisfactory,  so  all  infected  branches  should 
be  cut  off  several  inches  below  any  signs  of  the  knot.  A\'hen 
possible,  it  is  best  to  commence  this  pruning  with  the  young 
trees  as  it  sometimes  requires  severe  treatment  to  remove  all 
knots.  This  should  be  kept  up  each  year  until  the  knots  fail 
to  reappear.  In  case  the  tree  is  severely  cut  back,  additional 
pruning  is  needed  from  time  to  time  to  re-shape  the  tree,  remove 
water  sprouts,  etc.  The  knots  should  be  carefully  gathered  up 
and  burned  before  spring.  Watch  should  be  kept  of  wild 
cherry  and  plum  trees  in  the  neighborhood,  lest  they  serve  as  a 
means  of  infection. 

Winter  Spraying. 

Spraying  of  orchard  trees,  when  dormant,  was  first  made 
necessary  in  Connecticut  from  ten  to  fifteen  years  ago  by  the 


WINTER    SPRAYING.  5 

prevalence  of  the  San  Jose  Scale,  which  ruined  many  peach 
■orchards  and  seriously  damaged  apple  orchards.  Winter 
spraying  is  practiced  for  the  purpose  of  destroying  insects 
rather  than  fungi,  though  one  fungus,  the  peach  leaf  curl,  may 
also  be  controlled  by  this  treatment. 

Besides  the  San  Jose  Scale,  certain  other  pests,  such  as  the 
leaf  blister  mite  on  pear  and  apple,  the  clover  mite  which  may 
be  found  on  any  kind  of  trees,  the  pear  Psylla  on  pear,  the 
green  apple  aphis  and  the  rosy  apple  aphis  on  apple,  may  all  be 
wholly  or  partially  controlled  by  the  winter  treatment. 

For  most  of  the  insect  troubles  mentioned  above,  the 
trees  may  be  sprayed  as  soon  as  the  leaves  drop  in  November, 
or  just  before  the  buds  open  in  April.  The  fall  application  will 
probably  kill  more  San  Jose  scales  than  the  spring  application, 
because  they  are  not  then  protected  by  their  winter  covering 
and  often  the  naked  young  may  be  seen  crawling  about  until 
December  1st.  Where  trees  are  badly  infested  with  San  Jose 
Scale,  it  is  usually  advisable  to  spray  twice,  once  in  November 
and  again  in  April,  as  the  second  will  often  cover  parts  of  the 
tree  that  were  missed  by  the  first  treatment. 

For  peach  leaf  curl,  however,  the  early  spring  treatment  is 
advisable,  and  some  newly-hatched  aphids  will  then  be  killed 
which  were  not  present  on  the  trees  at  the  time  of  the  Novem- 
ber application. 

What  To  Use. 
Lime-Sulphur  Mixtures. 

The  best  all-round  spray  for  peach,  plum  and  all  young  and 
smooth-barked  trees  is  the  lime-sulphur  mixture.  In  some  of 
the  larger  orchards  this  is  made  on  the  place  which,  no  doubt, 
is  the  cheapest  and  best  way,  if  the  size  of  the  orchard  war- 
rants the  outlay  for  the  plant.  In  most  cases,  however,  the 
owner  will  prefer  to  purchase  his  lime-sulphur,  and  he  can 
buy  the  commercial  liquid  lime-sulphur  in  any  desired  quanti- 
ty, ready  to  dilute  and  apply,  and  be  fairly  certain  of  procur- 
ing a  good  article.  This  commercial  lime-sulphur  should  test 
about  33°B  and  it  should  be  diluted  at  the  rate  of  one  part 
in  nine  parts  of  water. 

There  are  now  on  the  market  several  dry  lime-sulphur  mix- 


6  CONNECTICUT  EXPERIMENT  STATION     BULLETIN    184. 

tures  which  claim  a  great  saving  in  freight  by  not  shipping  the 
water.  Some  of  these  are  sulphides  of  basic  elements  other  than 
lime,  and  they  will  probably  prove  good  insecticides  and  pos- 
sibly fungicides,  without  causing  injur}'  to  the  trees,  but  they 
are  still  more  or  less  in  the  experimental  stage. 

Miscible   Oils. 

If  one  has  large  and  old  apple  trees  with  rough  bark  and 
badly  infested  with  San  Jose  Scale,  he  may  be  able  to  rid  them 
of  the  scale  quicker  by  spraying  with  one  of  the  so-called  sol- 
uble or  miscible  oils,  such  as  "Scalecide",  "Carboleine"  or 
"Jarvis  Compound"  than  with  lime-sulphur,  because  the  oils 
have  a  greater  penetrating  power  and  will  go  into  the  cracks 
and  crevices.  It  will  also  moisten  the  pubescent  twigs  and 
"crawl"  around  them.  These  oils  should  be  diluted  at  the  rate 
of  one  part  to  fifteen  parts  of  water. 

Lime-Sulphur  versus  Miscible   Oils. 

The  oils  are  not  so  good  fungicides  as  is  lime-sulphur  and, 
when  they  do  not  mix  freely  with  water,  are  liable  to  cause 
injury  and  should  not  be  used.  There  is  no  danger  of  injuring 
dormant  trees  with  the  lime-sulphur  mixtures.  Moreover 
newly  hatched  scales  will  establish  themselves  readily  on  bark 
which  was  sprayed  with  oil  preparations  in  the  spring,  but  they 
do  this  very  sparingly  on  bark  treated  with  lime-sulphur : 
consequently,  if  any  are  present  they  are  found  on  the  new 
growth^ — twigs,  leaves,  or  fruit. 

At  the  Station  farm,  Mt.  Carmel,  in  the  old  and  neglected 
orchard  of  about  fifty  trees,  some  of  which  were  badly  infested, 
the  San  Jose  Scale  has  been  controlled  satisfactorily  for  four 
years  by  the  use  of  lime-sulphur, — no  miscible  oil  ever  having 
been  used.  The  trees  are  now  nearly  free  from  scale,  but  for 
two  years  they  were  given  both  fall  and  spring  treatments. 

SUMMER  SPRAYING. 
Apple. 
In  the  average  apple  orchard  only  two  summer  spray  treat- 
ments need  be  given,  the  first  soon  after  the  blossoms  fall  and 
the  second  from  three  to  four  weeks  later,  tlie  spray  being  lead 


SUMMER    SPRAYING.  ■  J 

-arsenate  (3  lbs.  of  the  paste,  or  l^^  lbs.  dry,  in  50  gallons  of 
water)  to  kill  the  codling  moth  or  apple  worm  which  is  always 
present;  and  usually  combined  with  some  fungicide  such  as 
commercial  L.  &  S.  (1>4  gallons).  The  beginner  should  fol- 
low this  simple  treatment  until  he  learns  what  special  troubles 
lie  needs  to  control,  and  unless  somewhat  familiar  with  spray- 
ing practices,  he  may  be  confused  by  the  more  complicated 
•combination  formulas  and  directions  for  controlling  the  various 
pests.     He  should  begin  at  the  bottom  and  "work  up". 

For  the  orchardist  more  experienced  in  spraying  and  iden- 
tifying- insect  and  fungous  pests,  we  recommend  the  following 
three  treatments,  or  such  as  he  may  need,  for  controlling  the 
particular  enemies  of  his  orchard : 

(1).  In  certain  localities  and  in  certain  seasons,  canker 
worms,  bud  moths,  tent-caterpillars  and  brown-tail  moths  may 
do  great  damage.  In  case  any  or  all  of  these  are  present  the 
worms  feed  on  the  unfolding  leaves,  and  a  spray  of  lead  arsen- 
ate should  be  given  before  the  blossom  buds  open,  though  not 
until  there  is  considerable  expanded  leaf-surface  to  hold  the 
poison.  If  scab  and  rust  are  prevalent,  a  fungicide,  preferably 
Bordeaux  mixture,  4-4-50,  should  be  added  to  the  poison  for 
this  treatment,  or  if  the  insects  mentioned  above  are  not 
troublesome,  it  may  be  used  alone. 

(2).  After  the  blossoms  fall  the  experienced  orchardist 
Avill  use  a  fungicide,  preferably  dilute  lime-sulphur,  1^  gallons 
in  50  gallons  of  water."  Where  there  is  little  danger  of  rus- 
scting  the  fruit,  weak  Bordeaux  mixture  (which  is  a  better 
fungicide)  1-4-50,  may  be  used  instead  of  lime-sulphur.  Lead 
arsenate  should  be  added  in  either  case.  If  there  is  a  prospect 
of  considerable  damage  from  aphlds,  leaf-hoppers,  scale- 
insects,  red-bugs,  or  pear  Psylla,  a  40  per  cent,  nicotine  solu- 
tion, Yz  pint  per  barrel,  may  be  added  to  the  combination  with- 
out injury  to  the  foliage  and  without  impairing  the  insecticidal 
or  fungicidal  properties  of  the  mixture. 

(3).  The  combined  fungicide-insecticides  just  mentioned 
may  be  used  for  the  June  or  third  spra3ang  but  the  nicotine  may 
not  then  be  necessary.  This  third  spraying"  takes  care  of  the 
second  brood  of  codling  moth,  late  chewing  insects,  etc.,  also 
the  sooty  blotch,  late  scab  and  various  fruit  specks  and  rot 
fungi. 


s        connecticut  experiment  station   bulletin  184. 

Pear. 

As  a  rule  pears  do  not  require  so  much  summer  spraying  as 
apples  and  the  treatments  are  given  for  specific  troubles.  It 
may  be  advisable  to  apply  poison  for  codhng  moth,  pear  slug 
and  other  leaf-eating  insects,  and  a  fungicide,  preferably  Bor- 
deaux, to  control  leaf  blight  and  scab.  Occasionally  nicotine 
may  be  needed  to  control  plant  bugs  or  the  pear  Psylla.  The 
applications  should  be  made  at  the  same  three  periods  as  for 
apples ;  namely,  on  the  unfolding  leaves  before  the  blossoms 
open,  just  after  the  petals  fall,  and  about  three  weeks  later. 

In  case  pear  blight  is  serious  despite  the  winter  pruning, 
summer  pruning,  with  especial  care  not  to  spread  infection  by 
means  of  the  pruning  tools,  is  sometimes  desirable. 

Peach. 

Peach  foliage  seldom  needs  to  be  sprayed  with  poison.  In 
Connecticut  orchards  the  peach  sawfly  has  caused  partial  defo- 
liation and  in  such  cases  one  spraying  with  lead  arsenate  (2  lbs. 
paste  in  50  gallons  water)  should  be  given  about  the  middle  of 
June.  This  may  be  added  to  the  self-boiled  lime-sulphur, 
w'hich  is  the  safest  fungicide  for  controlling  scab  and  brown 
rot.  - 

Scab  can  usually  be  controlled  by  two  treatments, — one  on 
the  young  fruit  about  the  middle  of  May,  and  another  the 
middle  of  June,  while  rot  is  often  largely  pre^•ented  by  two 
treatments  about  the  middle  of  June  and  July.  Three  treat- 
ments, about  the  middle  of  each  of  these  months,  will  take 
care  of  both  troubles  fairly  well.  Summer  spraying  is  most 
advisable  in  case  of  such  badly  rotting  varieties  as  Champion, 
etc.,  or  when  Elberta,  etc.,  scab  badly.  It  has  hardly  come  into 
general  practice  in  this  state,  but  deserves  more  attention  than 
has  yet  been  given  it.  Atomic  Sulphur  has  proved  as  satis- 
factory in  our  experiments  as  the  self-boiled  lime-sulphur  in 
controlling  these  two  fungi. 

Plum. 

Plum  orchards  may  need  to  be  sprayed  occasionally  witli 
poison  to  prevent  damage  from  canker  worms  or  other  leaf- 
eating  insects.    Some  writers  recommend  this  treatment  against 


SUMMER    SPRAYING.  V 

curculio,  but  probably  the  jarring  method  of  control  will  usu- 
ally be  found  more  satisfactory. 

For  the  control  of  brown  rot  the  fruit  should  be  thinned, 
and  after  harvest  all  mummies  should  be  gathered  and  destroyed. 
While  spraying  is  not  entirely  satisfactory,  largely  because  the 
spray  does  not  adhere  readily  to  the  smooth  fruit,  it  may  be 
desirable  in  certain  cases.  The  first  treatment  should  be  made 
with  self -boiled  lime-sulphur  on  the  fruit  when  about  half 
grown,  and  be  followed  by  a  second,  third,  and  possibly  fourth 
spraying  in  case  of  late  ripening  varieties,  at  intervals  of  ten 
to  fourteen  days.  The  last  spraying  should  be  made  about 
seven  to  ten  days  before  picking,  and  can  be  made  with  com- 
mercial lime-sulphur,  1-150,  if  there  is  any  danger  of  sediment 
on  the  fruit  interfering  with  its  sale.  In  case  of  leaf  an- 
thracnose,  the  spraying  should  be  started  earlier.     See  Cherry. 

Cherry. 

Rarely  is  it  necessary  to  spray  cherries  except  for  the  con- 
trol of  brown  rot  on  the  sweet  varieties,  and  for  this  purpose 
the  self-boiled  lime-sulphur  should  be  used,  the  same  as  direct- 
ed for  plum. 

In  case  the  leaf  spot  "anthracnose"  is  troublesome,  the  spray- 
ing should  be  made  earlier  than  for  brown  rot,  the  first  applica- 
tion being  made  on  the  young  leaves  just  after  the  petals  falU 
followed  by  one  or  two  others  at  intervals  of  ten  to  fourteen 
days. 

Occasionally  there  may  be  damage  from  the  pear  or  cherry 
slug,  in  which  case' a  weak  lead  arsenate  mixture  (say  2  lbs.  in 
50  gallons)  may  be  applied.  Unless  the  insects  are  present, 
however,  it  may  well  be  omitted. 

Quince. 

Quince  trees,  like  apples,  should  be  sprayed  with  lead  ar- 
senate and  a  fungicide,  preferably  Bordeaux  mixture.  Three 
treatments,  as  for  scab  of  apple  and  pear,  are  usually  desirable. 
These  help  to  control  rust,  black  rot,  leaf  blight,  and  such 
chewing  insects  as  are  present.  Summer  pruning  for  the 
bacterial  blight  may  be  desirable  in  some  cases. 


10       CONNECTICUT   EXPERIMENTAI.   STATION    BUI.I.ETIX    184. 

DIRECTIONS  FOR  MAKING  SPRAY  MIXTURES. 

Commercial  Lime-Sulphur.  Any  of  the  commercial  lime- 
sulphur  mixtures  on  the  market  testing  about  33°  B.  may  be 
used  for  spraying  fruit  trees.  For  winter  treatment  these 
are  usually  diluted  with  one  part  of  the  mixture  to  9  parts  of 
water.  For  summer  treatment  the  dilution  is  usually  l/i  to  l^/i 
gallons  to  50  gallons  water. 

Self-Boiled  Lime-Sulphur.  This  is  a  home-made  mixture 
prepared  as  follows :  Eight  pounds  of  fresh  lime  are  started 
slaking  in  a  barrel  with  a  little  water  (warm  water  preferably 
in  cool  weather),  and  when  the  mass  has  begun  to  heat,  eight 
pounds  of  sulphur  flour  are  quickly  sifted  in  and  thoroughly 
stirred  with  the  slaking  lime.  This,  at  the  consistency  of  a 
rather  thick  paste,  is  allowed  to  heat  for  fifteen  minutes  from 
the  time  the  sulphur  is  added,  when  it  is  cooled  down  with 
additional  water.  The  mixture  is  stirred  and  strained  into  the 
spray  barrel,  to  remove  the  coarser  sediment,  and  diluted  to 
the  fifty  gallons. 

Usually  three  barrel  lots  can  be  made  at  a  time  in  an  ordin- 
ary barrel  by  using  three  times  the  amount  indicated  above. 
This  amount  furnishes  more  heat  and  makes  a  little  better 
mixture  than  when  made  up  in  single  barrel  lots.  A  third  of  the 
amount  is  then  used  with  a  barrel  of  water. 

Bordeaux  Mixture.  Four  pounds  of  copper  sulphate  are 
dissolved  in  hot  water  or  by  suspending  the  crystals  in  a  coarse 
bag  in  a  half  barrel  of  water.  Four  pounds  of  fresh  lime  are 
slaked  in  a  small  amount  of  water,  and  then  strained  into  the 
spray  barrel  about  half  filled  with  water.  To  this  is  then  added 
the  half  barrel  of  dilute  copper  sulphate. 

When  several  barrels  are  needed,  stock  solutions  can  be 
made  up  as  follows:  The  copper  sulphate  is  dissolved  in  a 
barrel  at  the  rate  of  one  pound  to  one  gallon  of  water,  and  the 
lime,  after  slaking,  is  diluted  so  that  it  also  contains  one  [xmnd 
per  gallon  of  water.  Then,  when  needed,  four  i;allon>  of  the 
lime  water,  after  stirring  thoroughly,  arc  strained  into  the 
spray  barrel,  this  half  filled  with  water,  and  t'our  gallons  of 
the  copper  solution,  furtlier  diluted  to  make  about  half  a  Iiarrel. 
are  poured  into  this. 


RECEIPTS  FOR  SPRAYING  MIXTURES.  11 

Lead  Arsenate.  This  poison  is  manufactured  in  both  paste 
and  powder  form.  The  paste  form  is  generally  preferred  for 
orchard  work,  but  it  dries  and  becomes  lumpy  if  kept  from 
oiie  year  until  jthe  next.  '  It  also  corrodes  metal  containers. 
The  paste  contains  fifty  per  cent,  wafer  and  should  be  used  in 
the  proportions  of  3  lbs.  in  50  gallons  of  water.  It  is  best  to 
first  mix  it  thoroughly  with  a  small  amount  of  water  before 
putting  into  the  spray  tank:  t 

Dry  or  powdered  lead  arsenate  will  keep  indefinitely  in  a  dry 
place.  In  spraying,  use  just  half  as  much  as  of  the  paste  form, 
or  1^  lbs,  in  50  gallons  of  water.  The  dry  lead  arsenate  may 
be  thrown  into  the  spray  tank  after  it  has  been  filled  with 
liquid,  and  it  will  be  readily  moistened  and  distributed. 

Both  paste  and  powdered  lead  arsenate  may  be  used  in  con- 
nection with  lime-sulphur,  Bordeaux  mixture,  or  nicotine  solu- 
tion and  larger  quantities  of  arsenate  may  be  used  if  desired. 

Nicotine  Solutions.  Several  of  these  are  now  sold  contain- 
ing forty  per  cent,  or  more  of  nicotine,  usually  in  the  form  of 
sulphate.  For  most  kinds  of  aphids  one-half  pint  to  a  barrel 
of  water  is  sufficient,  but  the  amount  may  be  much  increased  or 
doubled  without  danger  of  causing  injury.  Nicotine  solutions 
may  be  safely  used  in  combination  with  lead  arsenate,  Bor- 
deaux mixture,  or  lime-sulphur;  with  any  one  or  with  all  of 
them. 

Miscible  Oils.  Several  brands  are  now  on  the  market,  and 
for  dormant  spraying  each  should  be  diluted  at  the  rate  of  one 
part  in  15  parts  water.  The  contents  of  each  original  package 
should  be  thoroughly  mixed  or  shaken  before  attempting  to 
dilute  any  portion  of  it.  As  a  rule,  it  is  unnecessary  and  in- 
advisable to  mix  miscible  oils  with  other  spray  materials. 
Such  oils  are  chiefly  used  on  dormant  trees. 

CAUTIONS. 

Before  beginning  to  spray,  know  what  you  are  spraying  for. 
If  you  have  troubles  which  you  cannot  identify,  send  speci- 
mens to  the  Station  and  get  information  and  advice. 

Never  spray  any  fruit  tree  while  in  bloom.  It  kills  your 
best  friends,  the  honey  bees,  which  pollinate  the  flowers  and 


12         CONNECTICUT  EXPERIMENT  STATION     BULLETIN    184. 

help  to  increase  the  yield  of  fruit.  The  spray  will  also  injure 
the  delicate  floral  organs,  so  that  fruit  will  not  set. 

Be  careful  about  using  any  kind  of  spray  not  advocated  here, 
especially  on  peach  and  Japan  plum  foliage,  which  are  especial- 
ly susceptible  to  spray  injury. 

If  miscible  oils  do  not  mix  readily  and  thoroughly  with 
water  on  diluting,  they  should  be  discarded,  as  there  is  danger 
of  injuring  the  trees. 


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